A blood component measuring device includes an irradiation light source configured to emit light at least in a near-infrared region, a light receiver having such sensitivity as to receive light emitted by the irradiation light source, a holding mechanism that holds and fixes a living body part, and an arithmetic device that calculates the concentration of a blood component in the living body part. The calculating means calculates the concentration of the blood component about, of the living body part, a place where the ratio of transmitted light intensity at a first wavelength relatively easily absorbed by hemoglobin and transmitted light intensity at a second wavelength relatively poorly absorbed by hemoglobin is the minimum.
